The invention relates to multi-station strip metal forming presses of the type including a vertically reciprocating ram for mounting and operating the tools. These presses are well suited for the manufacture of metal parts made sequentially in a succession of drawing operations at the stations. In this type of machine, coil strip stock is fed in widths from a fraction of an inch through up to seven inches on the larger machines. Blanks are automatically cut from the strip, and vertical blank transfer mechanism positively holds and carries the blank down to the transfer level, where it is picked up by the transfer fingers of a horizontal transfer mechanism. Usually the blank is transferred through a succession of draw dies in as many as fifteen individual work stations and, finally, ejected as a completed part. This type of completely automatic operation allows piercing, forming, drawing, lettering, embossing and flanging, as well as side slotting, side piercing and reverse drawing at production rates which have exceeded 250 l parts per minute. From blanking operation to finished part ejection, all tooling is mounted in standardized precision die sets to facilitate set up and minimize down time. Each station may be individually adjusted or serviced. Complete die sets can be interchanged without losing tool adjustment. Frequent complete change of jobs or intricate toolings will justify extra die sets.
An example of an early press of this type developed by the assignee of the instant application which sets forth the essential nature of this type of press is found in U.S. Pat. No. 2,049,915 dated Aug. 4, 1936, in the name of Arthur J. Lewis and assigned to the assignee of the instant application. Of course, a large number of improvements have been made since the issuance of the Lewis patent, primarily with a view toward producing higher speeds, lower ultimate tooling costs, precision operation, tool adjustment and replacement, minimizing down time, minimizing scrap loss and, in general, providing greater versatility and operational sophistication for the presses.
The type of press to which my invention pertains, for practical and economic reasons, comes in a limited number of configurations, that is, size, tonnage capability, size of stock which may be accommodated and the ultimate size of the part which may be manufactured on the press, including the maximum draw that can be made on a part. Although there are a number of variables that enter into the maximum draw that may be formed on a press of the type involved, such as the metallurgy of the strip material of which the part is being formed, one of the critical inhibiting factors is the inherent configuration of the machine. The amount of draw permitted by any given press is the result of the longest ram-tool stroke that can be achieved in any given size machine. For example, there is here reproduced a specification chart setting forth the specifications of five different size Multiple Transfer.RTM. presses that are manufactured by the assignee of the instant application, which do not include my inventive double punch extender.
SPECIFICATIONS __________________________________________________________________________ Specifications-Multiple Transfer Presses __________________________________________________________________________ Size of Press 2-19 3-25 4-37 5-51 5L-51 __________________________________________________________________________ Rated machine capacity tons 15 25 45 75 75 (kg) (13608) (22680) (40823) (68039) (68039) Stroke of ram - normal inches 1 1/2 2 2 1/2 3 7 (mm) (38.1) (50.8) (63.5) (76.2) (177.8) Stroke of ram - max. inches 2 3 5 5 7 (mm) (50.8) (76.2) (127) (127) (177.8) Shut height space for die set inches 8 5/8 10 14 1/2 18 20 from ram step to press bed (mm) (219.08) (254.00) (368.30) (457.20) (508.00) Ram width inches 18 7/8 24 7/8 36 7/8 50 7/8 50 7/8 (mm) (479.4) (631.8) (936.6) (1292.2) (1292.2) Transfer stroke - normal inches 1 3/4 2 3 3 1/2 4 or 4 1/2 (mm) (44.45) (50.8) (76.2) (88.9) (101.6 or 114.3) Transfer stroke - max. inches 2 1/2 3 4 1/2 5 1/2 5 1/2 (mm) 63.5) (76.2) (114.3) (139.7) (139.7) Motor HP & motor RPM 3-1750 5-1750 10-1150 10-1150 15-1150 Speed range - strokes per min. 105-275 110-260 60-160 40-90 40-90 Floor space side to side inches 48 58 1/4 87 1/2 113 1/4 113 1/4 (mm) (1220) (1480) (2220) (2880) (2880) Side to side with OSHA guards inches 61 76 1/2 103 121 121 (mm) (1550) (1940) (2620) (3070) (3070) Floor space front to rear inches 28 1/2 33 1/2 62 1/2 64 1/2 64 1/2 (mm) (725) (850) (1590) (1640) (1640) Front to rear with OSHA guards inches 51 62 68 81 81 (mm) (1300) (1575) (1730) (2060) (2060) Overall machine height inches 74 1/4 79 3/4 102 3/4 116 1/4 116 1/4 (mm) (1886) (2026) (2610) (2953) (2953) Height with OSHA guards inches 81 1/4 88 3/4 111 125 1/2 125 1/2 (mm) (2064) (2255) (2820) (3188) (3188) Net weight with die set lbs. 3350 5400 14500 25400 26500 (kg) (1520) (2450) (6580) (11520) (12020) Shipping weight lbs. 3650 5700 15000 25900 27000 (kg) (1656) (2585) (6800) (11750) (12250) Maximum width of inches 3 1/4 3 7/8 4 1/2 6 5/8 6 5/8 metal stock from roll feed (mm) (82.55) (98.43) (114.3) (168.6) (168.6) Maximum length of inches 2 3/4 3 3 1/4 4 4 stock from roll feed (mm) (69.85) (76.2) (82.55) (102) (102) __________________________________________________________________________ Max Ram Max Ram Max. Ram Max. Ram Max. Ram Draw Stroke Draw Stroke Draw Stroke Draw Stroke Draw Stroke __________________________________________________________________________ *Longest draw with 5/8 1 1/2 11/16 2 1 2 1/2 1 1/4 3 3 7 norm. ram stroke (15.9) (38.1) (17.5) (50.8) (25.4) (63.5) (31.8) (76.2) (76.2) (177.8) *Maximum draw with 13/16 2 1 1/4 3 1 5/8 4 2 1/4 5 3 7 maximum ram stroke (20.6) (50.8) (31.8) (76.2) (41.3) (101.6) (57.2) (127.) (76.2) (177.8) __________________________________________________________________________ Die Width or Max Blank Max. Blank Die Width or Max Blank Max. Blank No. of Tr. Stroke Diameter Diameter No. of Tr. Stroke Diameter Diameter Stations in. (mm) in. (mm) in. (mm) Stations in. (mm) in. (mm) in. (mm) __________________________________________________________________________ Press Size 2-19 9 4 (101.60) 2 1/2 (63.50) 2 3/4 (69.85) 7 2 1/2 (63.50) 1 1/2 (38.10) 1 3/4 (44.45) 10 3 1/2 (88.90) 2 1/4 (57.15) 2 3/4 (69.85) 9 2 (50.80) 1 1/4 (31.75) 1 3/4 (44.45) 12 3 (76.20) 2 (50.80) 2 1/2 (63.50) 10 1 3/4 (44.45) 1 (25.40) 1 7/16 (36.51) 14 2 1/2 (63.50) 1 1/2 (38.10) 2 (50.80) 11 1 1/2 (38.10) 3/4 (19.05) 1 7/16 (36.51) Press Size 5-51 Press Size 3-25 9 5 1/2 (139.70) 3 1/4 (95.25) 3 3/4 (95.25) 8 3 (76.20) 2 (50.80) 2 1/4 (57.15) 10 5 (127.00) 3 1/4 (82.55) 3 3/8 (85.73) 9 2 1/2 (63.50) 1 1/2 (41.28) 2 1/4 (57.15) 11 4 1/2 (114.30) 2 1/4 (69.85) 3 1/8 (85.73) 11 2 (50.80) 1 1/4 (31.75) 1 7/8 (47.63) 12 4 (101.60) 2 1/2 (63.50) 3 1/8 (85.73) 13 1 3/4 (44.45) 1 (25.40) 1 7/8 (47.63) 14 3 1/2 (88.90) 2 1/4 (57.15) 3 (76.20) 15 1 1/2 (38.10) 1/4 (19.05) 1 1/2 (38.10) Press Size 5L-51 Press Size 4-37 11 4 1/2 (114.30) 2 3/4 (69.85) 3 7/8 (98.43) 8 4 1/2 (114.30) 2 3/4 (69.85) 2 3/4 (69.85) 12 4 (101.60) 2 1/2 (63.50) 3 7/8 (98.43) __________________________________________________________________________ *When full size blank must be transferred to 2nd Station. *When blank and cup operation is performed at 1st Station.
It is the purpose of my invention to extend the maximum draw that may be obtained with any given machine and to increase it beyond its maximum as set forth in the foregoing chart by the incorporation of my unique double punch extender into the press. It will be understood that for many part manufacturing operations, for example, a thin aluminum part, a smaller size machine may have adequate tonnage, but inadequate maximum draw capacity. It is in these situations that the utilization of my double punch extender has the effect of permitting a smaller size machine to produce a part of a drawn length that would otherwise require the next larger size machine. Obviously, this is a great advantage to owners of existing presses of the type involved, for it enhances the ability of their presses to manufacture larger parts, i.e., parts that are larger in drawn length than they otherwise could form in the absence of my double punch extender.